3D‐Printed Strong Dental Crown with Multi‐Scale Ordered Architecture, High‐Precision, and Bioactivity

Abstract

Mimicking the multi-scale highly ordered hydroxyapatite (HAp) nanocrystal structure of the natural tooth enamel remains a great challenge. Herein, a bottom-up step-by-step strategy is developed using extrusion-based 3D printing technology to achieve a high-precision dental crown with multi-scale highly ordered HAp structure. In this study, hybrid resin-based composites (RBCs) with "supergravity +" HAp nanorods can be printed smoothly via direct ink writing (DIW) 3D printing, induced by shear force through a custom-built nozzle with a gradually shrinking channel. The theoretical simulation results of finite element method are consistent with the experimental results. The HAp nanorods are first highly oriented along a programmable printing direction in a single printed fiber, then arranged in a layer by adjusting the printing path, and finally 3D printed into a highly ordered and complex crown structure. The printed samples with criss-crossed layers by interrupting crack propagation exhibit a flexural strength of 134.1 ± 3.9 MPa and a compressive strength of 361.6 ± 8.9 MPa, which are superior to the corresponding values of traditional molding counterparts. The HAp-monodispersed RBCs are successfully used to print strong and bioactive dental crowns with a printing accuracy of 95%. This new approach can help provide customized components for the clinical restoration of teeth.

Digital Light Processing 3D‐Printed Silica Aerogel and as a Versatile Host Framework for High‐Performance Functional Nanocomposites

“…As demonstrated in Figure 3f , compared to nanofiller reinforcement strategies or designing organic–inorganic hybrid double cross‐linked polymer networks, nanocomposites with bicontinuous interpenetrating phases achieved significant mechanical superiority through synergistic load sharing and energy dissipation. [ 36 , 46 , 47 , 48 , 49 ] Of particular note is that, when striving for high mechanical properties, the dispersion problems and high viscosity associated with high nanofiller content in resins limited processability using vat photopolymerization methods of 3D printing. [ 2 , 50 ] In contrast, we offer a post‐printing cast‐in‐place strategy that is compatible with commercial DLP printers and provides a powerful and cost‐efficient solution for the additive manufacturing of high‐performance nanocomposites.…”

Advanced materials and technologies for oral diseases

“…(f) Construction process of the multi-scale highly aligned HAP nanorod structures. Reproduced by permission from [ 24 ], copyright 2021, Wiley.…”

“…(h) Nano Ceramic Crown. Reproduced by permission from [ 24 ], copyright 2021, Wiley. (i) Nanosensors for oral gas detection.…”

Surface Functionalization of Hydroxyapatite Scaffolds with MgAlEu‐LDH Nanosheets for High‐Performance Bone Regeneration

“…[ 13 , 14 , 15 ] However, HAp scaffold suffers from some disadvantages such as weak osteoinductive ability, poor cell crawling, and adhesion properties, resulting in the slow bone repair efficiency. [ 16 , 17 ] To this end, various methods have been developed to enhance the bioactivity and cell crawling/adhesion properties of HAp scaffolds, such as creating porous surface via 3D printing [ 18 , 19 , 20 ] or surface modification to promote the cell adhesion and differentiation, [ 21 , 22 , 23 , 24 ] and doping or surface modification with bioactive elements to improve the bioactivity of HAp scaffold. [ 25 , 26 , 27 ] For example, reduced graphene oxide (rGO) has been used to modify the surface of porous HAp to prepare 3D porous HAp/rGO scaffolds with a hierarchical structure.…”